Brake shoe



Jm- 31 11939- w. H. Wim-ERS MMWR BRAKE SHOE Filed Jan. e. 1937 ifi Patented `ian. 3l, i939 STATES .nati

PATENT OFFECE BRAKE SHOE awa/TE Application li'anuary 6, 1937, Serial No. 119,196

4 Claims.

This invention relates to brake shoes having a reenforce embedded in the body at the back thereof and more particularly to cast iron brake shoes having a reenforce in the nature of a steel plate embedded in the body at the back thereof.

In such. brake shoes the plate has been made as wide as possible to insure maximum strength, a margin about three-eights of an inch having been provided between the side edge of the plate back and the adjacent side of the shoe. This margin is sufficient to permit the body metal to make anchoring engagement with the side edges of the plate during casting but has not always been sufcient to provide substantial anchorage for the projections which extend up from the body of the shoe to enclose the sides of the lug strap of the attaching lug at the center of the shoe and by which lug the shoe is attached to the brake head. The practice heretofore had been to recess or upset the side edges of the plate back to provide anchorage for the projections embracing thel lug strap which somewhat impaired the strength of the back at the center attaching lug.

In the patent to Pogue 2,035,720, patented March 3l, 1936, there is disclosed a plate back in which the side edges of the back are continued without interruption or deformation beneath the attaching lug in such a way that the strength of the back is substantially unirnpaired at the attaching lug, and in the present invention the arrangement of this Pogue patent is preferably, though not necessarily, utilized.

One of the functions of the reenforcing back is to hold the parts of the body of the shoe together in event of fracture of the body which may occur in service. The invention of the aforesaid Pogue patent aifords reenforcement and insures against separation of the reenforce and body especially in those instances where the line of fracture of the shoe is adjacent the attaching lug, and the primary object of the present invention is to so interconnect the body and the reenforcing back that separation of the body and back will be prevented in event of fracture of the body intermediate the center attaching lug and one of the ends of the shoe.

Another important object of the present invention is to provide interlocking portions on the body and the back intermediate the center attaching lug and ends of the shoe so that separation of the body and back in event of a fracture of the body intermediate the attaching lug and an end of the shoe will be prevented.

More specically the objects are to form an- (Cl. 18S-258) choring lugs on the body engageable in complementarily shaped openings in the reenforcing back; to so form the anchoring lugs and openings that separation of the body and back longitudinally and transversely of the shoe in event of fracture of the body intermediate the center attaching lug and an end of the shoe will be prevented; and to form portions on the back engageable with the body in such a way as to cooperate with the anchoring lugs formed thereon to further insure against separation of the body and back in event of fracture of the body at a location as. above described.

Other and ancillary objects will be apparent from the following description wherein reference is made to the accompanying drawing in which selected embodiments of the invention are shown and wherein Fig. 1 is a side elevation, partly in elevation and partly in section, of a brake shoe embodying the invention;

Fig. 2 is a top plan view of a reenforce back according to this invention and wherein the outline of a shoe is shown in broken lines;

Fig. 3 is a transverse sectional View taken substantially on the line 3 3 on Fig. 1;

Fig. 4 lis a fragmentary view, similar to Fig. 2, and showing another form of the invention; and

Fig. 5 is a sectional view taken substantially on the line 5-5 on Fig. 4.

In the drawing the body 6 of the shoe is, as is customary in the art, preferably of cast iron and in accordance with the art may be provided with chilled sections and may have inserts of different kinds embedded therein. The reenforcing back 'i is a ductile metal plate that is embedded in the body at the back, the cast iron flowing around this back when the shoe is cast. The center attaching lug comprises the lug strap 9 bent to form a keyway 3a and having its end sections projected through parallel longitudinal slots ia in the back and bent inwardly against the under side of the back at 8b. The marginal side edges 9 of the back are depressed and a crowned central portion is formed therebetween. The crowned central portion lies above the depressed marginal edges of the back and is generally iiush with the back of the body. The marginal side edges of the back are not recessed or upset near the attaching lug or elsewhere but are continuous near the attaching lug and throughout at least the central portion of the shoe and preferably throughout the length of the back. The slots 'la through which the lug strap extends project longitudinally of the back CII and are of a size just sufficient to receive the lug strap. Therefore the width of the reenforcing back is maintained at and adjacent the attaching lug and the strength of the back is not reduced either here or elsewhere by recessing or upsetting its marginal edges.

- As is customary in the art, openings I are provided in the back adjacent the ends thereof through which portions of the body metal flow to form buttons that anchor in these openings to interconnect the body and the back at the ends of the shoe.

Heretofore it has been customary to provide openings in the back intermediate the openings I@ and the center attaching lug, such openings being shown in the above referred to Pogue patent. However, such openings were usually of regular outline and the body metal which flowed thereinto in the casting operation was, of course, complementary to such openings, and while such openings tended to interconnect the body and the back it has been found that openings of regular outline are not always sufficient to prevent separation of the body and back in event of a fracture of the body intermediate the center attaching lug and an end of the shoe.

Hence I provide openings II intermediate the openings Il) and the center attaching lug. In the form of the invention shown in Figs. 2 and 3 these openings I I include an intermediate restricted portion or neck IIa interconnecting enlarged substantially circular end portions IIb whereby the openings II are substantially in the shape of a dumb-bell having the longitudinal extent thereof extended longitudinally of the back. The side walls of the neck IIa are bent downwardly to provide depending flanges I2. In casting a shoe embodying a back having openings such as the openings II the molten metal flows through the openings II and forms attachment lugs I 3 on the body Which are shaped and which have an outline complementary to the openings 'Ihe effect of providing such irregularly shaped openings and the formation of complementarily shaped lugs on the body of the shoe fitted in such openings is that if the body fractures intermediate the center attaching lug and the end of the shoe the interengagement between the lug on the body and edges of the opening in the back prevents separation of the body parts from the back. It will be apparent that if the body tends to move longitudinally the end portions of the lug on the body will engage the edges of the enlarged end porti-ons IIb of the openings wherefore such longitudinal movement will be prevented, and this would be true even if a portion of the body aligned with the restricted portion IIa should fall out. It will thus be seen that a secure interlock between the parts of a fractured body and the back is afforded. Furthermore the engagement of the lug on the body with the edges of the enlarged portions IIb as well as with the edges of the restricted portion IIa effectively prevents movement transversely of the shoe which further insures against separation of the body from the back, and the engagement of the flanges I 2 with the lug on the body also prevents such transverse separation.

In the form of the invention illustrated in Figs. 4 and 5 an even more positive interlock between the body and back is provided. In this instance the back I is formed like the back 'I and has openings Ill therein like the openings I0. However here openings I4 are provided intermediate the center attaching lug and the openings I0. The openings I4 include a relatively elongated restricted intermediate portion or neck Illa and enlarged substantially kidney-shaped end portions Idb. The edges of the back along the restricted portion Ida are bent downwardly to provide inclined flanges I5 which incline downwardly and inwardly and the inner edges of which define the restricted portion Illa. In the casting operation in which the back 'I' is embedded in the body 6' anchor lugs I6 are formed by the body metal flowing through the openings I4, and these lugs are shaped and have an outline complementary to the openings I4. Portions of the anchor lugs I6 therefore overlie the inwardly inclined anges I5. The openings I4 and the complementarily shaped lugs I6 not only function as do the openings II and the complementarily shaped lugs I3 to prevent longitudinal and transverse separation of the back and body but also, by reason of the lugs I6 overlying the flanges I5, separation of the body and back in a direction away from the inwardly disposed face of the back is effectively prevented whereby especially in event of a plurality of fractures portions of the body are prevented from falling away from the back.

It will be apparent from the foregoing description that by providing openings in a reenforcing back of a brake shoe intermediate the center attaching lug and the end of the shoe and by imparting an irregular outline to these openings so that lugs will be formed on the body in the casting operation complementary to these openings, separation of the body and back of a shoe, especially in event of fracture, is effectively prevented. Furthermore by providing inwardly inclined flanges on the back along the edges of openings located as just described, separation of the body away from the inner face of the back is effectively prevented and all of these things represent a marked advance in the brake shoe art.

While I have illustrated and described selected embodiments of my invention, it is to be understood that these are capable of variation and modication and I therefore do not wish to be limited to the precise details set forth but desire to avail myself of such changes and alterations as fall within the purview of the following claims.

I claim:

l. A brake shoe having a body and a re'enforce plate anchored at the back thereof, said plate having an opening therein comprising a restricted intermediate portion and enlarged end portions, at least one marginal edge of the restricted part of said opening being deformed to provide a depending flange on said back to prevent longitudinal and transverse separation of the body and back in event of fracture of the body adjacent said opening.

2. A brake shoe having a body and a reenforce plate anchored at the back thereof, said plate having an opening therein comprising a restricted intermediate portion and enlarged end portions, at least one marginal edge of the restricted part of said opening being deformed to provide an inwardly and downwardly depending flange on said back, and a lug formed on the body of an outline complementary to the outline of said opening and engageable with the edges of said opening and said flange to prevent longitudinal and transverse separation of the body and back in event of fracture of the body adjacent said lug, said lug also cooperating with said flange to prevent separation of said body and back in a direction away from the inwardly disposed face of said back.

3. A brake shoe having a body, a reenforce plate anchored at the back thereof, and a center attaching lug, said plate having an opening therein intermediate the center attaching lug and one end of the shoe, said opening being elongated longitudinally of the plate and comprising a restricted intermediate portion and enlarged end portions, the marginal edges of said restricted portion being deformed to provide depending anges on said back, and a lug formed on said body and engageable with the edges of said opening and said flanges to prevent longitudinal and transverse separation of the body and back in event oi fracture of the body adjacent said lug.

4. A brake shoe having a body, a reenforce plate anchored at the back thereof, and a center attaching lug, said plate having an opening therein intermediate the center attaching lug and one end of the shoe, said opening being elongated longitudinally of the plate and comprising a restricted intermediate portion and enlarged end portions, the marginal edges of said restricted portion being deformed to provide inwardly and downwardly depending flanges on said back, and a lug formed on said body and engageable with the edges of said opening and said flanges to prevent longitudinal and transverse separation of the body and back in event of fracture of the body adjacent said lug, said lug also cooperating with said flanges to prevent separation of said body and back in a direction away from the inwardly disposed face of said back.

WILBUR H. WINTERS. 

